Flame thrower



June 12, 1962 B. B. FOWLER FLAME THROWER Filed Jan. 12, 1959 IN V ENTOR. BLAIR B. F OWLE I? ate Ohio

Filed Jan. 12, 1959, Ser. No. 786,348 14 Claims. (Cl. 158-28) Thepresent invention relates to means for igniting a stream of fuel andparticularly to the ignition of fuel projected under pressure from anozzle as a rod-like stream, as in flame throwers.

In a flame thrower it is an important requirement that adequate range beobtained and one consideration to be met is that the fuel stream shouldleave the nozzle with minimum interference in order that the kineticenergy of the liquid stream he conserved as much as possible while atthe same time the stream should ordinarily reach its target aflame sothat complete combustion of the fuel shot from the flame thrower resultson the restricted target area fired at. Of equal importance is the factthat the range attainable with a fuel stream is doubled or even tripledwhen properly ignited.

It is an object of the invention to provide ignition means for a flamethrower by which means the nozzle is surrounded by a body of flamewhirling about the axis of the jet of fuel so that the surface of thejet is ignited without interference with the main body of the jet.

It is a further object of the invention to utilize the fuel in the flamethrower for ignition of the stream of fuel by providing a fuel bleeddirecting a small jet of fuel in the form of a spray into a chamber orflame cone surrounding the nozzle and igniting said spray by meansserving also to ignite a propellant grain or charge, the burning ofwhich serves to pressurize the fuel in the flame thrower tank, burningof the sprayed fuel after initial ignition being self-supporting.

It is another object of the invention to provide an igniting devicehaving a chamber surrounding the nozzle and an orifice through which theignited stream of fuel from the flame thrower is ejected, said orificebeing surrounded by the intake of a casing surrounding the chamberhaving orifices connecting the casing to the chamber behind the openingof the nozzle so that the envelope of air entrained by the jet causes areduced pressure to be set up in the casing resulting in a rush of airat atmospheric pressure to enter said casing and supply the air requiredto maintain the body of flame surrounding the nozzle after the spray offuel has been ignited.

With the above and other objects in view, which will appear from thefollowing specification and accompanying illustrative drawings, theinvention comprises a fuel nozzle provided with a conduit from which asecondary spray of fuel is projected into a chamber surrounding thenozzle, said chamber having an open end positioned ahead of the nozzlefor the passage of'a compact stream of fuel ejected through said nozzle,means to ignite said secondary spray, and a casing surrounding saidchamber and having a wall spaced from the wall of said chamber andaround the open end of said chamber for the entry of'atmospheric airaround the open end of the chamber and into the space between the wallsof said chamber and easing, said chamber and casing being incommunication behind the forward end of the nozzle whereby air issupplied to maintain the flame of said secondary spray around the nozzleto cause ignition of the surface of said compact stream of fuel issuingfrom said nozzle.

In the drawings:

FIG. 1 is a fragmentary perspective and sectional view of the nozzle ofa flame thrower, the section being taken partly vertical to the'aXialline of the nozzle and partly horizontal to said axis.

FIG. 2 is a detail View in front elevation partly in section of thenozzle of the flame thrower and tank closure on which it is mounted, thenozzle being sectioned on the line 2-2 in FIG. 3.

FIG. 3 is a side elevation of the parts shown in FIG. 2'.

FIG. 4 is a fragmentary perspective View, drawn on a larger scale, ofthe delivery end of the nozzle, showing parts normally mounted thereinwithdrawn therefrom.

FIG. 5 is a front view drawn on a larger scale of an air directingmember arranged in a chamber surrounding the nozzle.

FIG. 6 is a cross-sectional view of the igniter element.

Referring to FIG. 1, the numeral '10" indicates a portion of the shroudcovering the operative parts of the flame thrower. The subject flamethrower is operable on either liquid or thickened (jelled) fuels whichare commonly used in flame thrower applications. The fuel under pressureexits the nozzle in similar form with either liquid or jelled fuel, thatis, a rod-like stream of fuel. The liquid fuel disperses rapidly afterbeing emitted and ignited from the nozzle into a billowy flame frontwhile the thickened or jelled fuel can be used for long range flamethrowing purposes wherein the time for ignition of the jelled fuel isgreater in respect to the liquid fuel and the flame front issubstantially restrictive. Jelled fuels generally allow a longer maximumrange for the flame thrower While liquid fuels can cover a greater areaat a much shorter relative range. The problem, of course, is the matterof ignition of a liquid versus a jelled fuel. Partial ignition of anyfuel reduces efficiency, therefore, a greater amount of attention isdirected to the method of ignition.

A conical flame cone 1]; is mounted Within the shroud 10 and is spacedfrom the wall thereof by spacing blocks I12 and rivets 13. The flamecone 1 projects for a considerable distance beyond the delivery end ofthe nozzle.

The flame cone 11 is flattened in the area 13a on its inward side andits open end 14 is spaced peripherally from the edge 15 of an opening inthe shroud 10 through which the concentrated stream of fuel, or fuelrod, 16 is ejected.

The nozzle 17 from which the fuel rod is ejected under high pressure islocated axially in the flame cone 11, and is carried by a closure 18screwed into the head casting 19 of the flame thrower to which thepressurized source of fuel 19a is attached. A ball check Valve 1%,attached to the source of fuel 190, may be used to admit pressurized airor the like, the closure '18 closing the delivery end of the tank.

The main fuel passage 20 in the nozzle is stepped down in diametertoward the end of the nozzle ending in length of bore of relativelysmall diameter.

A passage 21 for a secondary flow offuel is drilled from the innersurface of closure 18 longitudinally through the wall of the nozzle andconnects with a transverse passage 22 drilled through the wall of thenozzle adjacent its outer end. The arrangement of the passages isclearly shown in FIGS. 2, 3 and 4. One end of passage 22 is closed bythe threaded plug 23 and the opposite end 24 is reduced in diameterproviding a peripheral shoulder 25. The reduced end 24 is positionedopposite the flattened portion 27 so that the secondary supply of fuelis dispersed or splashed causing it to envelop the entire fuel rod. Aspinner 26 is mounted in purposes. The direction'inwhich the flameof-the ig-. entering h o g h o r pp blades The fuel nition charge isdirected into the flame cone ischosen' 's'oasnot' to disrupt thefuel-rod, the .flame of the igni- 'tion charge travelling inthesarne'direction as the-fuel,

rod.

stream of fuel. :The purpose. of the swirling action is to completelysurround the' rod-like stream of fueland, prein the flame cone by theinjeYctoraction-of the fuel-rod I heing'ejected therethrough at highspeed. Air from outside the front end of the flamethrowerflows through.

the gap a between the shroud 10 and flame'cc-ne 11 and over the outsideof the flame cone 11 into the space behind the'air-dire'cting and:fiameholding jmember- I The air enters it behind the end'of the nozzleas indicated'by the: arrows in FIG. 1.

In order to give the air a 'whlrling motion and aid in, preventing theflame from spreading back from. the. flame cone, the flame holdermember29 is mounted on the back of the flame cone 1-1 and extends radiallyinwardly toward the nozzle. I The member 29 as shown in FIG. 5 comprisesa sheet metal ring 30 cut partway through from: oneedge at, a I

plurality of points, the cut portions being bent at right I angles to.the ring and-twisted to form overlapping blades 30a. The ring of metalis: flattened on one. side to. lie

over and against the flattened portion 13:: of the flame I cone and isriveted thereto. -The inwardly projecting blades are cut away attheilocation oftheigniter 28..

While a common ignition means is indicated which ig- I I -=nites thepropellant grain pressurizing the tank of the flame throwersimultaneously with the ignition. of the secondary fuel injected intothe flame cone, the igniter- I for the. secondary jet may --be fired byelectrical glow plug means and may be provided as a. separate ignite:

, from that for the propellant tankpressurizing device, the:

-.-separate: igniters being controlled by one trigger thus enabling astraighttank to be arsed,- or a tank containing fuel put under pressureby acompre'ssed gas-might be used,.the trigger-operated igniter servingonly to ignite the secondary fuel: jet in the flame cone.

The flame in the flame cone is maintained in a swirling path in contactwith the fuel rod issuing from the nozzle and remains in contact withthe surface of the rod for a distance sufficient to ignite the surfaceof the fuel rod which travels through the air burning only on its outersurface to a point at which the decreasing speed of the fuel rod end dueto air resistance and vaporizing of the fuel toward the end of the fuelrod due to its continued surface burning causes scattering of the endinto droplets resulting in dropping of the fuel rod end unless the fuelstream impinges against a target. On impingement, the burning streamsplatters and envelops the target in flame.

Operation Initially all openings in the shroud nozzle and igniter areclosed by means such as plugs or discs which are blown out of place whenthe trigger of the flame thrower is operated to cause ignition of thegas generator. Pressure is thereafter immediately applied to the tank,forcing a concentrated stream of fuel or fuel rod through the nozzle andflame cone and projecting it from the flame thrower. The secondarystream of fuel is emitted from the reduced end 24 after it is dispersedor broken by the whirling spinner 26 and still being under the pressureof the source from which it was received, it is forced against theflattened portion 13a. The dispersed secondary supply of fuel splashesor disperses within the flame-containing housing to surround the rodlikestream of fuel and simultaneously is ignited by the charge emitted bythe igniter element 28. This envelope of flame composed of ignitedparticles of the secondary fuel tend to be swirled by the swirlingaction of the inclined direction of the restricted orriiice 24 strikingthe flattened portion 130 plus the swirling action of the air vent merepartial ignition of the main stream of fuel. Ignition devices which .donot. completely envelop the main stream of fuel enhance'the possibilityof partial ignition and reduce the efliciency of the entire flamethrowing'purpose. I I.

A preferred embodiment of invention has been I specifically describedand shown in the accompanying drawings. by way of illustration. but notaslimitative of the invention since various modifications may be-made inthe described embodiment by those skilled in the art I without.departing .fromthe. scope of the invention. as

defined by the appended. claims.

I claim: I I 1. Ina flame thrower; means for igniting and projecting aconcentrated streamof pressurized fuelcomprising: I I

a source of pressurized fuel; a fuel nozzle in supplying I relationtosaid pressurizing fuel and adapted to project; a

rod-dike streamoffuel; a 'fiame'c'oritainin'g housing surrounding saidnozzle and projecting beyond the end means to disperse said secondarysupply of fuel to completely' surround said-rod-li ke stream of fuel;means for thereof; means for projectingasecondary supplyof fuel intosaid housing at an angle to the axis of-the fuelnozzle; I

initiating ignition of said secondary supplyof fuel toproe I duce flamewithin said housing surrounding the rod-like stream of fuel adjacentitsexit from the nozzle .to effect surface ignition .of'said rod-likestream:

of fuel; and,

means providing for the flow of air into said housing to.

maintain the combustion .of said secondary fuel.

'2. In a flamethrower, meansfor igniting and proiect- I I ing aconcentrated stream of pressurized fuel comprising:

a source of pressurized fuel; a fuel nozzle in supplying relation tosaid pressurized'fuel and adapted to project. a. I I I rod-like streamof fuel; a flame-containing conical housing I I I I surrounding saidnozzle and having an opening at the narrower end thereof positioned tosurround the rod-like stream of fuel at a point spaced beyond the exitof the fuel from the nozzle and the wider end of the housing surroundingsaid nozzle; means projecting a secondary sup ply of fuel into saidhousing; means to disperse said secondary supply of fuel to completelysurround said rodlike stream of fuel; means for initiating ignition ofthe dispersed secondary supply of fuel to produce flame within saidhousing surrounding the rod-like stream of fuel adjacent its exit fromthe nozzle to effect surface ignition of said rod-like stream of fuel;and means providing for the flow of air into said housing to maintainthe combustion of said secondary fuel.

3. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel comprising: a source of pressurized fuel; afuel nozzle in supplying relation to said pressurized fuel and adaptedto project a rod-like stream of fuel; a flame-containing conical housinghaving an opening at the narrower end thereof positioned to surround therod-like stream of fuel at a point spaced beyond the exit of the fuelfrom the nozzle and the wider end of the housing surrounding saidnozzle; an annular member projecting inwardly from said wider end of thehousing and formed to provide blades causing whirling of air enteringthe wider end of the housing; means projecting a secondary supply offuel into said housing; means to disperse said secondary supply of fuelto completely surround said rod-like stream of fuel; means forinitiating ignition of the dispersed secondary supply of fuel to produceflame within said housing surrounding the rod-like stream of fueladjacent its exit from the nozzle to elfect surface ignition of saidrod-like stream of fuel; and means providing for the flow of air intosaid housing through said blades to maintain the combustion of saidsecondary fuel.

4. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel, comprising: a source of pressurized fuel; afuel nozzle in supplying relation to said pressurized fuel and adaptedto project a rod-like stream of fuel; a shroud enclosing said nozzle andprovided with an opening through which an ignited stream of fuel isprojected; a conical flame containing housing surrounding said nozzleand projecting beyond the end thereof having an opening at the narrowerend thereof positioned within but spaced from the perimeter of theopening in the shroud affording an opening for the free passage of airbetween said shroud and said housing and positioned to surround therod-like stream of fuel at a point spaced beyond the exit of the fuelfrom the nozzle and the wider end of the housing surrounding saidnozzle; an annular member mounted on the wider end of said housing andprojecting inwardly therefrom and formed to provide blades causingwhirling of air entering the space between the perimeter of the openingin the shroud and the outer surface of said housing and entering thewider end of the housing; means projecting a secondary supply of fuelinto said housing; means to disperse said secondary supply of fuel tocompletely surround said rodlike stream of fuel; means for initiatingignition of the dispersed secondary supply of fuel to produce flamewithin said housing surrounding the rod-like stream of fuel adjacent itsexit from the nozzle to effect surface ignition of said rod-like streamof fuel; the combustion of said secondary fuel being maintained by theair entering the wider end of the flame housing.

5. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel, comprising: a source of pressurized fuel; afuel nozzle in supplying relation to said pressurized fuel and adaptedto project a rod-like stream of fuel; a conical flame containing housingsurrounding said nozzle and having an opening at the narrower endthereof positioned to surround the rod-like stream of fuel at a pointspaced beyond the exit of the fuel from the nozzle and the wider end ofthe housing surrounding said nozzle behind the forward end of thenozzle; said nozzle having a passage through the wall of said nozzlediverting a portion of the pressurized fuel supplied to said nozzle anddelivering said diverted fuel as a spray into said housing; means todisperse said portion of pressurized fuel to completely surround saidrod-like stream of fuel; means for initially igniting the dispersedspray of fuel to produce flame in said housing surrounding the rod-likestream of fuel adjacent and after its exit from the nozzle; and meansproviding for the flow of air into said housing to maintain thecombustion of said spray of fuel.

6. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel, comprising: a source of pressurized jelledfuel; a fuel nozzle in supplying relation to said pressurized jelledfuel and adapted to project a rod-like stream of fuel; a conical flamecontaining housing surrounding said nozzle and having an opening at thenarrower end thereof positioned to surround the rod-like stream of fuelat a point spaced beyond the exit of the fuel from the nozzle and thewider end of the housing surrounding said nozzle behind the forward endof the nozzle; said nozzle having a passage extending axially throughthe nozzle and communicating with said source of pressurized fuel; thewall of said nozzle having a passage therethrough and communicating withsaid source of pressurized fuel, and spinner means located in saidlatter passage whereby the fuel flowing through said passage isdelivered as a whirling spray into said flame housing; means to dispersesaid source of pres surized fuel flowing through the passage in the saidwall of said nozzle to completely surround said rod-like stream of fuel;means for initially igniting the dispersed spray of fuel to produceflame in said housing surrounding the rod-like stream of fuel adjacentand after its exit from the nozzle; and means providing a flow of airinto said housing to maintain the combustion of said spray of fuel.

7. In a flame thrower, means for igniting and projecting a concentratedstream of fuel as set forth in claim 6 and in which said latter passageis arranged to direct the whirling spray of secondary fuel against theinner surface of said housing.

8. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel comprising: a source of pressurized fuel; afuel nozzle in supplying relation to said pressurized fuel and adaptedto project a rod-like stream of fuel; a flame containing housingsurrounding said nozzle and projecting beyond the end thereof; means forproviding a flow of air into said housing to maintain the combustion ofsaid spray of fuel; means projecting a secondary supply of fuel intosaid housing; a flattened portion of said flame-containing housing beingaligned with said projecting means for said secondary supply fuelwhereby said secondary supply of fuel is dispersed in saidflame-containing housing completely surrounding said rod-like stream offuel; and an ignition member adapted to direct a flame into said housingto initially ignite the secondary fuel in said housing.

9. In a flame thrower, means for igniting and projecting a concentratedstream of fuel comprising: a source of pressurized fuel; a fuel nozzlein supplying relation to said pressurized fuel and adapted to project arod-like stream of fuel; a flame containing housing open at each end andsurrounding said nozzle and projecting at its forward end beyond theforward end of said nozzle; means projecting a secondary supply of fuelinto said housing; a flattened portion on said flame-containing housingbeing aligned with said projecting means for said secondary supply offuel whereby said secondary supply of fuel is dispersed in saidflame-containing housing completely surrounding said rod-like stream offuel; and an ignition member arranged to direct a flame into saidhousing in a direction to ignite said secondary fuel but to preventdisruption of said rod-like stream of fuel and means providing a flow ofair into said housing to maintain the combustion of said spray ofsecondary fuel.

10. In a flame thrower, means for igniting and projecting a rod-likestream of fuel, comprising: a source of pressurized fuel; a fuel nozzlein supplying relation to said pressurized fuel and adapted to projectsaid rod-like stream of fuel; a conical open ended flame containinghousing surrounding said nozzle with its narrower end projecting beyondthe forward end of the nozzle; said nozzle having a passage inclined atan angle to the direction of said rod-like stream of fuel and deliveringa spray of secondary fuel into said housing; a flattened portion of saidflame-containing housing being aligned with said secondary fuelpositioned substantially parallel to said rod-like stream of fuel; anignition means arranged to direct a flame for combustion of said spraywithin said housing in a direction preventing disruption of said rodlikestream of fuel; and means providing a flow of air into said housing tomaintain the combustion of said spray of secondary fuel.

11. Means for igniting and projecting a rod-like stream of fuel, as setforth in claim 10 and in addition comprising: means to establish a flowof air from outside the forward end of said coneshaped housing andguiding it into the back of the housing with a whirling motion.

12. In a flame thrower, means for igniting and projecting a concentratedstream of pressurized fuel comprising: a source of pressurized fuel; afuel nozzle in supplying relation to said pressurized fuel and adaptedto project a rod-like stream of fuel; a flame containing housingsurrounding said nozzle and projecting beyond the end thereof; means forprojecting a secondary supply of fuel into said housing at an angle tothe axis of said nozzle; a splash plate contained by saidflame-containing housing being aligned with said projecting means forsaid secondary supply of fuel and having a position substantiallyparallel to said rod-like stream of fuel whereby said secondary supplyof fuel will envelop said rod-like stream of fuel; means for initiatingignition of said secondary supply of fuel to produce flame within saidhousing and surrounding the rod-like stream of fuel adjacent its exitfrom the nozzle to elfect surface ignition of said rod-like stream offuel; and means providing for the flow of air into said housing tomaintain the combustion of said secondary fuel.

13. A flame thrower comprising: a pressurized fuel source, a fuel nozzlein supplying relation to said fuel source, said nozzle having a mainpassage adapted to project a rod-like stream of fuel, a comically-shapedhousing surrounding said nozzle and having its axis substantiallyconcentric with said rod-like stream of fuel and having a passageway forsaid stream of fuel positioned with its diverging portion forward ofsaid nozzle, a means for introducing a flow of air adjacent to saidrod-like stream of fuel and having a swirling motion, said nozzle havinga second passage adapted to project a secondary supply of fuel and insupplying relation with said fuel source,

said nozzles second passage terminating in anorifice projected at anangle to the direction of said rod-like stream of fuel, a splash platereceived by said housing aligned with said nozzle orifice and positionedto deflect said secondary supply of fuel in a swirling motion aroundsaid rod-like supply of fuel, and means to ignite said secondary supplyof fuel.

14. In the flame thrower as set forth in claim 13 in which said air flowintroducing means is a plurality of blades in said housing.

References Cited in the file of this patent UNITED STATES PATENTS1,304,710 Seidler May 27, 1919 1,797,654 Grund Mar. 24, 1931 2,480,147Letvin Aug. 30, 1949 2,497,939 Garraway et a1. Feb. 21, 1950 2,574,495Parker Nov. 13, 1951 2,669,296 Stillman et al Feb. 16, 1954 2,701,608Johnson Feb. 8, 1955 2,857,961 Brown 111 et a1. Oct. 28, 1958

